Thermal storage for co2 system

ABSTRACT

A climate control system may include a cooling system having a compressor in fluid communication with a condenser and a evaporator and circulating a first fluid therebetween; a first heat exchanger in fluid communication with the cooling system and operable to remove heat from a second fluid; a reservoir in fluid communication with the first heat exchanger and adapted to receive the second fluid; a pump in fluid communication with the first heat exchanger and the reservoir and circulating the second fluid therebetween; a second heat exchanger in selective fluid communication with the first heat exchanger, the reservoir and the pump; and a valve movable between a first position allowing fluid communication between the reservoir and the second heat exchanger and a second position preventing fluid communication between the reservoir and the second heat exchanger, wherein heat is absorbed by the second fluid flowing through the second heat exchanger.

FIELD

The present disclosure relates to a climate control system and moreparticularly, to a thermal storage system for a climate control system.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art. Many modern vehicles,such as automobiles, include climate control systems or air conditioningsystems that operate to cool a passenger compartment of a vehicle. Suchclimate control systems typically include a compressor to circulate arefrigerant or other working fluid through the system. The compressor isoften driven by the engine of the vehicle via a belt or other powertransmission means.

Gas-electric hybrid vehicles are becoming more popular as vehicle fuelefficiency becomes increasingly more important to modern consumers. Suchhybrid vehicles are often propelled by an internal combustion engine andan electric motor which may operate simultaneously or independently ofeach other to reduce the engine's fuel consumption. Continuous operationof the climate control system is often dependent upon continuous andefficient operation of the engine-driven compressor. Accordingly, areduction in the engine's output and/or deactivation of the engine in ahybrid vehicle may reduce the cooling capacity and/or interruptefficient operation of the cooling system. This may adversely affect adriver or passenger's comfort and enjoyment of the vehicle.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features. Inone form, the present disclosure provides a thermal storage system thatmay include a cooling system including a condenser, an evaporator and acompressor in fluid communication with the condenser and the evaporator.The compressor causes the circulation of a first fluid between thecondenser and the evaporator, and throughout the entire system. A firstheat exchanger may be in fluid communication with the cooling system andoperable to remove heat from a second fluid. A reservoir may be in fluidcommunication with the first heat exchanger and be adapted to receivethe second fluid. A pump may be in fluid communication with the firstheat exchanger and the reservoir and circulate the second fluidtherebetween. A second heat exchanger may be in selective fluidcommunication with the first heat exchanger, the reservoir and the pump.A valve may be movable between a first position, allowing fluidcommunication between the reservoir and the second heat exchanger, and asecond position, preventing fluid communication between the reservoirand the second heat exchanger. Heat may be absorbed by the second fluidflowing through the second heat exchanger.

In another form, the present disclosure may provide a climate controlsystem that may include a first fluid circuit. The first fluid circuitmay include an evaporator, an accumulator and a compressor. Thecompressor may cause the circulation of the first fluid through thefirst fluid circuit. A second fluid circuit may include a coil, areservoir, and a pump. The pump may cause the circulation of a secondfluid through the second fluid circuit. A heat exchanger may be inselective fluid communication with the second fluid circuit. A coil maybe disposed in an accumulator and the first fluid in the accumulator mayabsorb heat from the second fluid flowing through the coil. A valve maybe movable between a first position allowing the second fluid to flowthrough the heat exchanger and a second position causing the secondfluid to bypass the heat exchanger. A fan may be positioned to force airacross or through the evaporator and the heat exchanger.

In yet another form, the present disclosure may provide a climatecontrol system that may include a first fluid circuit that employs anevaporator, a first tube and a compressor, which circulates a firstfluid through the first fluid circuit. The system may further employ asecond fluid circuit including a second tube, a reservoir, and a pump tocirculate a second fluid through the second fluid circuit. A second heatexchanger may be in selective fluid communication with the second fluidcircuit. A valve may be movable between a first position allowing thesecond fluid to flow through the second heat exchanger and a secondposition causing the second fluid to bypass the second heat exchanger. Afan may be adapted to force air across or through the evaporator and thesecond heat exchanger. The first tube and the second tube may besubstantially coaxial and the first fluid flowing through the first tubemay absorb heat from the second fluid flowing through the second tube.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a schematic representation of a vehicle having a climatecontrol system according to the principles of the present disclosure;

FIG. 2 is a schematic representation of an embodiment of the climatecontrol system in a charging mode according to the principles of thepresent disclosure;

FIG. 3 is a schematic representation of the climate control system ofFIG. 2 in a discharging mode according to the principles of the presentdisclosure;

FIG. 4 is a partial perspective view of the climate control systemhaving an internal heat exchanger according to the principles of thepresent disclosure;

FIG. 5 is a schematic cross-sectional view of the internal heatexchanger according to the principles of the present disclosure;

FIG. 6 is a partial perspective view of the internal heat exchangerhaving a portion of an outer tube cut away;

FIG. 7 is a schematic representation of another embodiment of theclimate control system in a charging mode according to the principles ofthe present disclosure; and

FIG. 8 is a schematic representation of the climate control system ofFIG. 7 in a discharging mode according to the principles of the presentdisclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe FIGS. 1-8. A climate control system 10 is provided and may include aprimary cooling system 12 and an auxiliary cooling system or thermalstorage system 14, both of which may be installed in a vehicle 16 andmay cooperate to control a temperature within a passenger compartment ofthe vehicle 16. The vehicle 16 could be a hybrid vehicle selectivelypowered by an internal combustion engine 18 and an electric power source20, or both. The internal combustion engine 18 may power the primarycooling system 12 and the electric power source 20 may power the thermalstorage system 14.

The primary cooling system 12 may include a first fluid circuit having acompressor 22, a gas cooler or condenser 24, an internal heat exchanger26, an expansion device 28, an evaporator 30, and an accumulator 32. Thecompressor 22 may circulate or pump a first fluid, such as carbondioxide or R-134a, for example, through the primary cooling system 12.It will be appreciated that the first fluid could be any otherrefrigerant or coolant suitable to cool an automobile cabin.

The compressor 22 may be operable to draw relatively low pressure fluid,compress the fluid to a relatively higher pressure and discharge thefluid at the relatively high pressure. The compressor 22 can be areciprocating compressor, a scroll compressor, or a rotary vanecompressor, for example, or any other suitable type. The compressor 22may be driven by the internal combustion engine 18 via a belt or anyother suitable means of transmitting rotary power. The condenser 24 mayinclude a heat exchanger or coil having an inlet 34 adapted to receivethe high pressure fluid from the compressor 22. The fluid may rejectheat to the ambient air as it flows through the coil. The fluid may thenexit the condenser 24 through an outlet 36. It will be appreciated thatthe condenser 24 could be a gas cooler, a radiator, or any othersuitable heat exchanger. The expansion device 28 may be an expansionvalve or an orifice tube, for example, adapted to allow the first fluidto expand, thereby lowering the pressure and temperature of the fluid asit flows therethrough. The expansion device 28 may be fluidly coupledwith the internal heat exchanger 26 and the evaporator 30.

The evaporator 30 may include a heat exchanger or coil having an inlet38 adapted to receive the first fluid from the expansion device 28. Thefluid may absorb heat from the ambient air as it flows through the coil.The fluid may then exit the evaporator 30 through an outlet 40. A fan 42may force the ambient air across the coil of the evaporator 30 tofacilitate heat transfer therebetween. Air forced across the evaporator30 may be subsequently channeled through one or more ducts to thepassenger compartment of the vehicle 16, for example.

With more particular reference to FIG. 4-6, the internal heat exchanger26 may be disposed downstream of the condenser 24 and may include aplurality of generally coaxial tubes or pipes including an inner pipe44, an intermediate pipe 46, and an outer pipe 48. The inner pipe 44 mayinclude a first end 50 and a second end 52. The first end 50 may befluidly coupled to the outlet 36 of the condenser 24. The second end 52may be fluidly coupled to the expansion device 28. In this manner, highpressure fluid may flow from the condenser 24, through the inner pipe 44to the expansion device 28. The inner pipe 44 can have a generallycircular cross-section and may be formed from aluminum, steel, or anyother suitable material or combination of materials.

The intermediate pipe 46 may include a first end 54 and a second end 56.The first end 54 may be sealed around the inner pipe 44 and may includean inlet 58. The inlet 58 may be fluidly coupled to the outlet 40 of theevaporator 30. The second end 56 may also be sealed around the innerpipe 44 and may include an outlet 60. The outlet 60 may be fluidlycoupled to the accumulator 32. In this manner, the low pressure fluidexiting the evaporator 30 may flow through the intermediate pipe 46 tothe accumulator 32. The intermediate pipe 46 can have a generallycircular cross-section and at least a portion thereof may be spiraled,as depicted in FIG. 6, which may define a spiral or helical flow paththrough the intermediate pipe 46 between the outer diameter of the innerpipe 44 and the inner diameter of the intermediate pipe 46. The spiralportion may also define a spiral flow path through the outer pipe 48between the outer diameter of the intermediate pipe 46 and the innerdiameter of the outer pipe 48. The spiral flow path may increase heattransfer between the high pressure fluid flowing through the inner pipe44 and the low pressure fluid flowing through the intermediate pipe 46.The intermediate pipe 46 may be formed from aluminum, steel, or anyother suitable material or combination of materials.

The outer pipe 48 may include a first end 62 and a second end 64. Thefirst end 62 may be sealed around the intermediate pipe 46 and mayinclude an inlet 66. The second end 64 may also be sealed around theintermediate pipe 46 and may include an outlet 68. In this manner, asecond fluid may flow into the inlet 66, through the outer pipe 48 andexit through the outlet 68. The outer pipe 48 can have a generallycircular cross-section and may be formed from aluminum, steel, or anyother suitable material or combination of materials.

It will be appreciated that the internal heat exchanger 26 could beotherwise formed. The plurality of pipes 44, 46, 48 could have anysuitable geometry, and could include one or more non-coaxial pipes. Theaccumulator 32 may receive a mixture of liquid and vapor fluid from theintermediate pipe 46 of the internal heat exchanger 26. The accumulator32 may separate liquid and vapor portions of the fluid, store the liquidin a reservoir and allow the vapor to be drawn into the compressor 22.

The thermal storage system 14 may be a second fluid circuit and mayinclude a pump 70, the outer pipe 48 of the internal heat exchanger 26,a reservoir 72, a first valve 74, a second valve 75, a heat exchanger76, and a bypass line 77. The pump 70 may circulate a second fluid, suchas engine coolant (e.g., an ethylene glycol based coolant, a propyleneglycol based coolant, or any other suitable coolant), through thethermal storage system 14. As will be subsequently described, thethermal storage system 14 may charge or remove heat from the secondfluid while the compressor 22 is operating and may supplement thecooling capacity of the primary cooling system 12 when the compressor 22is deactivated or the cooling capacity of the primary cooling system 12is otherwise inadequate.

The pump 70 may be an electric pump and may be powered by the electricpower source 20 (FIG. 1) or any other battery. The pump 70 may be apositive displacement pump, for example, or any other suitable pumpadapted to circulate the second fluid through the thermal storage system14. The pump 70 may include an inlet 78, through which the second fluidmay be drawn, and an outlet 80, through which the second fluid may bedischarged. The outlet 80 may be fluidly coupled to the inlet 66 of theouter pipe 48 of the internal heat exchanger 26. In this manner, thesecond fluid may flow from the outlet 80 of the pump 70 into the inlet66, through the outer pipe 48 and exit through the outlet 68 of theouter pipe 48. As the second fluid flows through the outer pipe 48, heatfrom the second fluid may be absorbed by the first fluid flowing throughthe intermediate pipe 46.

The reservoir 72 may be a bottle, tank or other container adapted tostore the second fluid. The reservoir 72 may include an inlet 82 and anoutlet 84. The inlet 82 may be fluidly coupled to the outlet 68 of theouter pipe 48. The reservoir 72 may store additional fluid beyond theamount than can be circulating through the thermal storage system 14 atany given moment. Fluid entering through the inlet 82 may mix with thefluid stored in the reservoir 72, and a portion of the fluid therein mayexit through the outlet 84. The reservoir 72 may be formed from apolymeric material, for example, or any other insulating material. Thesize and shape of the reservoir 72 may be dictated by various factorsincluding vehicle packaging constraints, the desired cooling capacity ofthe thermal storage system 14, the thermal properties of the secondfluid, and/or other performance, space and cost requirements.

The outlet 84 of the reservoir 72 may be fluidly coupled to the firstvalve 74. The first valve 74 may be a three-way valve including an inlet86, a first outlet 88 and a second outlet 90. The first valve 74 may beselectively moveable between a first position and a second position. Inthe first position, the second fluid may be allowed to flow from thereservoir 72 into the inlet 86 and through the second outlet 90 to theheat exchanger 76. In the second position, the second fluid may beprevented from flowing through the second outlet 90 and reaching theheat exchanger 76 and instead may exit through the first outlet 88 andflow through the bypass line 77. The first valve 74 could be a solenoidvalve, for example, or any other suitable type of valve. A controller 92may be in electrical communication with the first valve 74 and may causethe first valve 74 to move between the first and second positions, aswill be subsequently described.

The heat exchanger 76 may include a coil through which the second fluidmay flow when the first valve 74 is in the first position. The heatexchanger 76 may be disposed proximate the evaporator 30 and generallyaligned therewith, such that the fan 42 may force air across the coil ofthe evaporator 30 and the coil of the heat exchanger 76. In this manner,heat from the air may be absorbed by the second fluid, thereby coolingthe air as it is forced across the coil of the heat exchanger 76.

The second valve 75 may be a three-way valve fluidly coupled to thebypass line 77, the heat exchanger 76 and the pump 70. The second valve75 may be adapted to prevent fluid received from the bypass line 77 fromflowing to the heat exchanger 76 and may be adapted to prevent fluidreceived from the heat exchanger 76 from flowing to the bypass line 77.The second valve 75 could be a check valve or solenoid valve incommunication with the controller 92, for example, or any other suitabletype of valve.

With continued reference to FIGS. 1-6, operation of the climate controlsystem 10 will be described in detail. As described above, the primarycooling system 12 may be a first fluid circuit operable to cool thepassenger compartment of the vehicle 16. When the cooling capacity ofthe primary cooling system 12 is insufficient to adequately cool thepassenger compartment of the vehicle 16, the thermal storage system 14(the second fluid circuit) may provide cooling capacity to cool thepassenger compartment, as will be subsequently described.

The thermal storage system 14 may be operable in a charging mode (FIG.2) and a discharging mode (FIG. 3). While the primary cooling system 12is operating, the thermal storage system 14 may operate in the chargingmode to cool the second fluid in the thermal storage system 14. Sincethe compressor 22 is driven by the engine 18, the primary cooling system12 may operate only while the engine 18 is operating. When the engine 18is shutoff or deactivated, the controller 92 may cause the thermalstorage system 14 to operate in the discharge mode, whereby the thermalstorage system 14 may cool the passenger compartment.

In the charging mode (FIG. 2), the first valve 74 may be in the secondposition, such that fluid may flow from the reservoir 72 to the bypassline 77 and may be prevented from flowing to the heat exchanger 76. Inthis manner, the pump 70 circulates the second fluid through the outerpipe 48 of the internal heat exchanger 26, through the reservoir,through the bypass line 77 and back to the pump 70, where the cycle maybe repeated. As described above, the first fluid absorbs heat from thesecond fluid in the internal heat exchanger 26. Therefore, as thethermal storage system 14 continues to operate in the charging mode, thesecond fluid flowing therethrough and stored in the reservoir 72 maycontinue to lose more and more heat (i.e., the second fluid becomesincreasingly colder). Since the reservoir 72 stores more fluid than thesystem can circulate at any given moment, the reservoir 72 can build-upadditional cooled (or charged) coolant, thereby increasing the coolingcapacity of the thermal storage system 14.

The controller 92 may switch the thermal storage system 14 into thedischarge mode by moving the first valve 74 into the first position,thereby allowing the second fluid to flow through the heat exchanger 76(FIG. 3). In this configuration, the second fluid may flow from the pump70, through the outer pipe 48 of the internal heat exchanger 26, throughthe reservoir 72, and through the coil of the heat exchanger 76, wherethe second fluid may absorb heat from the air forced over the coil bythe fan 42 and thereby provide cooled air to the cabin of a vehicle.From the heat exchanger 76, the fluid may flow back to the pump 70,where the cycle may be repeated.

The controller 92 may move the first valve 74 from the second position(the charging mode) to the first position (the discharging mode) inresponse to one or more of a plurality of predetermined conditions. Suchpredetermined conditions may include insufficient cooling capacity ofthe primary cooling system 12, shutdown or deactivation of thecompressor 22, and/or shutdown or deactivation of the engine 18. It willbe appreciated that in an embodiment where the vehicle 16 is a hybridvehicle, the engine 18 may be periodically deactivated in favor of theelectric power source 20 to reduce the fuel consumption of the vehicle16. Since the compressor 22 may be driven by the engine 18, deactivatingthe engine 18 may shutdown the primary cooling system 12. In such aninstance, the controller 92 may switch the thermal storage system 14into the discharging mode to maintain capacity of the climate controlsystem 10 to cool the passenger compartment of the vehicle 16.

If the primary cooling system 12 shuts down or is deactivated because auser (e.g., a passenger or driver) has turned off the air conditioningin the vehicle 16 (i.e., the air conditioning is no longer demanded),the first valve 74 may remain in the second position (the chargingmode), and/or the pump 70 may be shut down to discontinue operation ofthe thermal storage system 14.

Referring now to FIGS. 7, and 8, another embodiment of the climatecontrol system will be described and will be hereinafter referred to asthe climate control system 110. The climate control system 110 mayinclude a primary cooling system 112, a thermal storage system 114, andthe fan 42 described above. Similar to the climate control system 10described above, the primary cooling system 112 may be a first fluidcircuit operable to cool the passenger compartment of the vehicle 16.When the cooling capacity of the primary cooling system 112 isinsufficient to adequately cool the passenger compartment of the vehicle16, the thermal storage system 114 (a second fluid circuit) may providecooling capacity, such as additional cooling capacity, to cool thepassenger compartment to the temperature desired.

The primary cooling system 112 may include the compressor 22, thecondenser (or gas cooler) 24, the expansion device 28, and theevaporator 30, all of which may have substantially similar structure andfunction as described above with reference to the primary cooling system12. The primary cooling system 112 may also include an internal heatexchanger 126 and an accumulator 132. The primary cooling system 11 2may circulate the first fluid in a similar manner as described above.

The internal heat exchanger 126 may include a first pipe 144 and asecond pipe 146, which may be coaxial and include similar structures asany of the inner, intermediate and/or outer pipes 44, 46, 48 previouslydescribed above. For example, either or both of the first and secondpipes 144, 146 may include a circular or spiral cross-section, as shownin FIGS. 5 and 6. The first pipe 144 may be fluidly coupled to thecondenser 24 and the expansion device 28. The second pipe 146 may befluidly coupled to the evaporator 30 and the accumulator 132. Fluidflowing through the second pipe 146 may absorb heat from the fluidflowing through the first pipe 144.

The thermal storage system 114 may include the pump 70, the reservoir72, the first and second valves 74, 75, the heat exchanger 76, thebypass line 77, and controller 92, all of which may have substantiallysimilar structure and function as described above with reference to thethermal storage system 14. The thermal storage system 114 may alsoinclude a coil 148 fluidly coupled with the pump 70 and the reservoir72. The coil 148 may be disposed in the accumulator 132, such thatliquid fluid being stored in the accumulator 132 may at least partiallysurround the coil 148. In this manner, the first fluid in theaccumulator 132 may absorb heat from the second fluid flowing throughthe coil 148, thus lowering the temperature of the second fluid.

Operation of the climate control system 110 may be substantially similaras the operation of the climate control system 10 described above inthat the thermal storage system 114 may circulate the second fluid inthe charging mode and discharging mode. However, in the thermal storagesystem 114, the second fluid may be charged (i.e., cooled) as it flowsthrough the coil 148 disposed in the accumulator 132. In this manner,the coil 148 and the accumulator 132 function as a heat exchangeroperable to remove heat from the second fluid.

While the thermal storage systems 14,114 are described above as chargingthe second fluid via the internal heat exchanger 26 and the accumulator132, respectively, it will be appreciated that any other heat exchangercould be configured to remove heat from the second fluid to charge thethermal storage system 14, 114. It should also be appreciated that theclimate control system 10 could be used with any vehicle and is notlimited to hybrid vehicles, such as hybrid automobiles and hybridtrucks. Further, the climate control systems 10, 110 could be used tocool any space, and are not limited to cooling the passengercompartments of vehicles. The climate control systems 10, 110 could beused for non-vehicle applications such as buildings.

Stated in a slightly different manner, with reference to FIGS. 2 and 6,part of what has been disclosed above is a thermal storage systememploying a cooling system including a condenser 24, an evaporator 30and a compressor 22. The compressor 22 forces a first fluid through thecondenser 24 and the evaporator 30. Located in the cooling system loop,a first heat exchanger 26 utilizes the first fluid in fluidcommunication with the cooling system to cool, or remove heat, from asecond fluid (liquid). Additionally, a reservoir 72 for storing thesecond fluid may be in fluid communication with the first heat exchangervia the second fluid. A pump 70 circulates the second fluid, a liquid,through the first heat exchanger 26 and the reservoir 72. As depicted inFIG. 2, the first fluid is in a first closed system that fully containsthe first fluid, which changes states between a liquid and a gas, whilethe second fluid, which is a liquid, is also in its own containedsystem. Heat may be transferred between the first fluid and the secondfluid.

Continuing, a second heat exchanger 76 that is filled with the secondfluid, receives the second fluid from the reservoir. More specifically,the second fluid circulates from the pump 70, through the internal heatexchanger 26, into and through the reservoir 72, to the first valve 74,and then either to the second heat exchanger 76, or to the pump 70again, and therefore bypassing the second heat exchanger 76. The firstvalve 74 is movable between a first position, which allows the secondfluid to flow into the second heat exchanger 76 from the reservoir 72,and a second position, which allows the second fluid to bypass thesecond heat exchanger 76 and flow into the pump 70 to prevent fluidcommunication between the reservoir 72 and the second heat exchanger 76.A fan 42 blows air through the evaporator 30 and the second heatexchanger 76. The evaporator 30 and the second heat exchanger 76 may bearranged parallel to each other with a broad, flat side of each facingeach other so that the air blows through the evaporator 30 first andthen second heat exchanger 76. Heat is transferred from the air to thesecond fluid flowing through the second heat exchanger 76.

The thermal storage system may further employ a controller 92 and upondeactivation, that is turning off or discontinued rotation, of thecompressor 22, the controller 92 switches valve position to permit thesecond fluid to flow into the second heat exchanger 76. This switchingand utilization of the second heat exchanger 76 permits the vehiclecabin to have cool air blown into it by the fan 42. The internal heatexchanger 26 is adapted or designed to simultaneously receive the firstfluid and the second fluid to facilitate heat transfer between the twofluids. The internal heat exchanger is adapted to simultaneously receivethe first fluid from the condenser 24 in a first state (e.g. a liquid)and the first fluid from the evaporator in a second state (e.g. a gas).The thermal storage system may be installed in a hybrid vehicle. Thefirst fluid may be carbon dioxide and the second fluid may be a liquid,such as a typical engine anti-freeze solution.

When an element or layer is referred to as being “on”, “engaged to”,“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto”, “directly connected to” or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention. Individual elements or features ofa particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the invention, and all such modificationsare intended to be included within the scope of the invention.

1. A thermal storage system comprising: a cooling system including acondenser, an evaporator and a compressor, the compressor in fluidcommunication with the condenser and the evaporator and circulating afirst fluid therebetween; a first heat exchanger in fluid communicationwith the cooling system and operable to remove heat from a second fluid;a reservoir in fluid communication with the first heat exchanger andadapted to receive the second fluid; a pump in fluid communication withthe first heat exchanger and the reservoir to circulate the second fluidtherebetween; a second heat exchanger in selective fluid communicationwith the first heat exchanger, the reservoir and the pump; and a valvemovable between a first position allowing fluid communication betweenthe reservoir and the second heat exchanger and a second positionpreventing fluid communication between the reservoir and the second heatexchanger, wherein heat is absorbed by the second fluid flowing throughthe second heat exchanger.
 2. The thermal storage system of claim 1,wherein the second fluid flowing through the second heat exchangersupplements the cooling capacity of cooling system.
 3. The thermalstorage system of claim 1, further comprising a fan adapted to force airacross the evaporator and the second heat exchanger.
 4. The thermalstorage system of claim 1, wherein the valve allows the second fluid tothe second heat exchanger in response to deactivation of the compressor.5. The thermal storage system of claim 1, wherein the first heatexchanger is an accumulator.
 6. The thermal storage system of claim 1,wherein the first heat exchanger is an internal heat exchanger.
 7. Thethermal storage system of claim 6, wherein the internal heat exchangeris adapted to simultaneously receive the first fluid and the secondfluid to facilitate heat transfer therebetween.
 8. The thermal storagesystem of claim 7, wherein the internal heat exchanger is adapted tosimultaneously receive the first fluid from the condenser in a firststate and the first fluid from the evaporator in a second state.
 9. Thethermal storage system of claim 1, wherein: the cooling system isinstalled in a hybrid vehicle, the first fluid is carbon dioxide, thesecond fluid is engine coolant, and the valve allows the second fluid toflow to the second heat exchanger in response to deactivation of aninternal combustion engine of the hybrid vehicle.
 10. A climate controlsystem comprising: a first fluid circuit including an evaporator, anaccumulator and a compressor circulating a first fluid through the firstfluid circuit; a second fluid circuit including a coil, a reservoir, apump circulating a second fluid through the second fluid circuit, and aheat exchanger in selective fluid communication with the second fluidcircuit, wherein the coil is disposed in the accumulator and the firstfluid in the accumulator absorbs heat from the second fluid flowingthrough the coil; a valve movable between a first position, allowing thesecond fluid to flow through the heat exchanger, and a second positioncausing the second fluid to bypass the heat exchanger; and a fan adaptedto force air across the evaporator and the heat exchanger.
 11. Theclimate control system of claim 10, wherein the second fluid is cooledand stored while the valve is in the second position and the secondfluid cools the air forced across the heat exchanger while the valve isin the first position.
 12. The climate control system of claim 11,wherein: the valve moves between the first and second positions based atleast partially upon operation of the compressor and a demand for coolair, and the first fluid is carbon dioxide.
 13. A climate control systemcomprising: a first fluid circuit including an evaporator, a first tubeand a compressor circulating a first fluid through the first fluidcircuit; a second fluid circuit including a second tube, a reservoir, apump circulating a second fluid through the second fluid circuit, and asecond heat exchanger in selective fluid communication with the secondfluid circuit; a valve movable between a first position allowing thesecond fluid to flow through the second heat exchanger and a secondposition causing the second fluid to bypass the second heat exchanger;and a fan adapted to force air across the evaporator and the second heatexchanger, wherein the first tube and the second tube are substantiallycoaxial and the first fluid flowing through the first tube absorbs heatfrom the second fluid flowing through the second tube.
 14. The climatecontrol system of claim 13, wherein the second fluid is cooled andstored while the valve is in the second position and the second fluidcools the air forced across the heat exchanger while the valve is in thefirst position.
 15. The climate control system of claim 14, wherein: thevalve moves between the first and second positions based at leastpartially upon operation of the compressor and a demand for cool air,and the first fluid is carbon dioxide.
 16. A thermal storage systemcomprising: a cooling system including a condenser, an evaporator and acompressor, the compressor for forcing a first fluid through thecondenser and the evaporator; a first heat exchanger in fluidcommunication with the cooling system and operable to remove heat from asecond fluid; a reservoir for storing the second fluid, the reservoir influid communication with the first heat exchanger via the second fluid;a pump that circulates the second fluid through the first heat exchangerand the reservoir; a second heat exchanger that is filled with thesecond fluid and receives the second fluid from the reservoir; a valvemovable between a first position, which allows the second fluid to flowinto the second heat exchanger from the reservoir, and a secondposition, which allows the second fluid to bypass the second heatexchanger and flow into the pump to prevent fluid communication betweenthe reservoir and the second heat exchanger; and a fan for blowing airthrough the evaporator and the second heat exchanger, wherein theevaporator and the second heat exchanger are arranged parallel to eachother in a serial fashion so that the air blows through the evaporatorfirst and then second heat exchanger, and heat is transferred from theair to the second fluid flowing through the second heat exchanger. 17.The thermal storage system of claim 16, further comprising a controller,wherein upon deactivation of the compressor, the controller switchesvalve position to permit the second fluid to flow into the second heatexchanger.
 18. The thermal storage system of claim 17, wherein: thefirst heat exchanger is an internal heat exchanger, the internal heatexchanger is adapted to simultaneously receive the first fluid and thesecond fluid to facilitate heat transfer therebetween, and the internalheat exchanger is adapted to simultaneously receive the first fluid fromthe condenser in a first state and the first fluid from the evaporatorin a second state.
 19. The thermal storage system of claim 18, wherein:the thermal storage system is installed in a hybrid vehicle, the firstfluid is carbon dioxide, and the second fluid is a liquid.